This paper designed a circle-shaped Fresnel lens with large aperture as part of the solar pumped laser design project. The Fresnel lens designed in this paper simulate in size 1000mm×1000mm, focus length 1200mm and polymethyl methacrylate (PMMA) material in order to conduct high convergence efficiency. In the light of design requirement of concentric ring with same width of 0.3mm, this paper proposed an optimized Fresnel lens design based on previous sphere design and conduct light tracing simulation in Matlab. This paper also analyzed the effect of light spot size, light intensity distribution, optical efficiency under four conditions, monochromatic parallel light, parallel spectrum light, divergent monochromatic light and sunlight. Design by 550nm wavelength and under the condition of Fresnel reflection, the results indicated that the designed lens could convergent sunlight in diffraction limit of 11.8mm with a 78.7% optical efficiency, better than the sphere cutting design results of 30.4%.
Wireless laser power supply to long-distance devices is drawing more and more interest in recent years. As power receivers, laser cells are adhered on these devices. Relatively high laser cell efficiency could be obtained under a monochromatic illumination. In order to study the most efficient laser illumination conditions to the laser cell, the efficiencies of circular and rectangular cells illuminated by laser with fundamental mode are compared. The simulations show that the cell efficiency increases slowly with the increase of the laser power, and decreases with the increase of the spot size. When the rectangular cell and the circular cell have the same area, and the diameter of the circular cell and that of the laser spot are equal, the efficiency of the circular cell is higher than the rectangular cell.